JP2014099542A - Substrate delivery mechanism, substrate carrying device and substrate delivery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate delivery mechanism capable of preventing a substrate from being deviated when delivering the substrate.SOLUTION: A stage 18 of a load lock module 14 includes three lift pins 18a which are disposed on the same circumference in a planar view. A fork 17b of a carrier arm 17a includes three pads 17c formed from elastic bodies protruding upwards and abutted to a rear face of a wafer W. A pitch circle diameter of each of the lift pins 18a is set in such a manner that, when the wafer W is carried upwards by the lift pins 18a, the wafer W is positively deformed to be protruded upwards and the rear face of the wafer W is tilted with respect to a horizontal direction and when the tilted rear face of the wafer W is abutted to the three pads 17c, a force (e.g., a shear force 22) acting on the pads 17c along a direction tilted with respect to the horizontal direction is generated.

Description

  The present invention relates to a substrate transfer mechanism, a substrate transfer device, and a substrate transfer method using lift pins and transfer arms.

  In a substrate processing system that processes a wafer as a substrate in a single wafer, the wafer is transferred in a single wafer between modules constituting the substrate processing system, such as a loader module, a load lock module, a transfer module, and a process module. . In particular, in the load lock module, the wafer loaded from the loader module is lifted by lift pins and transferred to the fork of the transfer arm that has entered from the transfer module. The transfer arm carries the wafer into the process module and transfers it to lift pins protruding from the stage of the process module.

  9 is a diagram schematically showing the configuration of the transfer arm in the transfer module, FIG. 9 (A) is a perspective view of the transfer arm, and FIG. 9 (B) is a plan view of the fork of the transfer arm. FIG. 9C is a side view of the fork of the transfer arm. In FIG. 9B, the wafer is indicated by a broken line for convenience.

  In FIG. 9A, a transfer arm 90 includes a columnar base 91 that can rotate around a central axis, a scalar-type arm 92 that is disposed on an upper portion of the base 91 and can be expanded and contracted, And a fork 93 provided at the tip, and the wafer supported by the fork 93 is conveyed between the load lock module and the process module by turning and expanding / contracting.

  As shown in FIGS. 9B and 9C, the fork 93 is constituted by a bifurcated flat plate member, and has three pads 94 arranged on the same circumference on the upper surface. Each pad 94 is a protrusion made of an elastic body, for example, heat-resistant rubber, and comes into contact with the back surface of the wafer W when the fork 93 supports the wafer W.

  In the process module, the wafer needs to be placed at a predetermined position (processing position) on the stage. Therefore, when the wafer W is transferred by the transfer arm 90, the relative position of the wafer W relative to the fork 93 and each stage is generated. In order to prevent the wafer W from shifting, the pad 94 is in contact with the back surface of the wafer W so as to maintain as large a contact area as possible.

  However, since the amount of thermal expansion of the wafer has increased as the diameter of the wafer has increased in recent years, the difference in the amount of thermal expansion between the wafer W and the fork 93 also increases, so that the contact between the back surface of the wafer W and each pad 94 can be maintained. There was a problem of disappearing.

  Therefore, a thin protrusion that abuts the back surface of the wafer W is provided at the tip of each pad 94, and when the wafer W is thermally expanded, the thin protrusion is positively deformed to reduce the difference in thermal expansion between the wafer W and the fork 93. A method of absorbing and maintaining the contact between the back surface of the wafer W and each pad 94 has been proposed (see, for example, Patent Document 1).

  Further, when the wafer W is lifted by a plurality of lift pins so that the pad 94 is appropriately brought into contact with the back surface of the wafer W, conventionally, the lift pins are arranged as far as possible on the outer peripheral side of the wafer W so as not to bend the wafer W. In order to support, the circumference (Pitch Circle Diameter) (hereinafter referred to as “PCD”) on which each lift pin is arranged is set as large as possible. Thereby, the bending of the wafer W is suppressed, and each pad 94 comes into contact with the back surface of the wafer W with a large area.

International Publication No. 2009/005027

  However, as the wafer diameter increases, the weight of the wafer increases and the back surface of the wafer W comes into close contact with each pad 94. Therefore, when the wafer W is transferred from the fork 93 to the lift pins of the process module, The wafer W may not be separated from the fork 93 just by adhering to the pad 94 and slightly lifting the wafer W with lift pins.

  In this case, it is necessary to lift the wafer W strongly with the lift pins, but the wafer W lifted with the lift pins while the wafer W is not separated from the pad is greatly warped. Therefore, when the wafer W is separated from each pad 94, the wafer W However, there is a problem that the position of each pad 94 shifts due to spring force caused by warpage.

  An object of the present invention is to provide a substrate delivery mechanism, a substrate transport apparatus, and a substrate delivery method that can prevent the substrate from being displaced during delivery of the substrate.

  In order to achieve the above object, the substrate delivery mechanism according to claim 1 is a substrate delivery mechanism comprising a plurality of lift pins for lifting the substrate upward in order to deliver the substrate to a substrate support provided on a transfer arm. The plurality of lift pins are arranged on the same circumference in a plan view, and the substrate support portion has a plurality of contact portions that protrude upward and are made of an elastic body that contacts the back surface of the substrate. The pitch circle diameter of the lift pins is such that when the plurality of lift pins lift the substrate upward, the substrate positively deforms upward and the back surface of the substrate is inclined with respect to the horizontal, and the inclined substrate is inclined. When the back surface of the contact member abuts against the plurality of contact portions, a force (for example, shearing force) acting in a direction inclined with respect to the horizontal to the plurality of contact portions is set. And

  A substrate delivery mechanism according to a second aspect is the substrate delivery mechanism according to the first aspect, wherein at least an upper end of the contact portion has a hemispherical shape.

  The substrate delivery mechanism according to claim 3 is the substrate delivery mechanism according to claim 1 or 2, wherein the substrate is made of a disk-like member having a diameter of 450 mm, and the pitch circle diameter of the plurality of lift pins is 180 mm or less. It is characterized by.

  According to a fourth aspect of the present invention, in the substrate delivery mechanism according to the third aspect, the pitch circle diameter of the plurality of lift pins is 120 mm or less.

  In order to achieve the above object, a substrate transfer apparatus according to claim 5 includes an atmospheric vacuum switching chamber, a substrate processing chamber, and a substrate transfer chamber interposed between the atmospheric vacuum switching chamber and the substrate processing chamber. In the processing system, a substrate transfer apparatus for transferring a substrate between the substrate processing chamber and the atmospheric vacuum switching chamber, wherein the substrate transfer device is disposed in the substrate transfer chamber, and can be moved back and forth to the atmospheric vacuum switching chamber and the substrate processing chamber. And a plurality of lift pins arranged in the atmospheric vacuum switching chamber and lifting the substrate upward to deliver the substrate to the substrate support unit, the plurality of lift pins being Arranged on the same circumference in plan view, the substrate support portion has a plurality of abutting portions that protrude upward and abut against the back surface of the substrate, and the plurality of lift pins. The pitch circle diameter of the substrate is such that when the plurality of lift pins lift the substrate upward, the substrate positively deforms upward and the back surface of the substrate is inclined with respect to the horizontal, When the back surface abuts on the plurality of abutting portions, the force is set so as to generate a force that acts on the plurality of abutting portions in a direction inclined with respect to the horizontal.

  To achieve the above object, the substrate delivery method according to claim 6 is a substrate delivery method for delivering a substrate with a plurality of lift pins to a substrate support provided on a transfer arm, wherein the substrate is delivered with the plurality of lift pins. A substrate raising step of supporting the vicinity of the center of the substrate with the plurality of lift pins and positively deforming the substrate upwardly so as to incline the back surface of the substrate with respect to the horizontal. A substrate lowering step in which the substrate is lowered by the plurality of lift pins and the substrate is supported by the substrate support portion while the substrate is supported by the plurality of lift pins, and the plurality of lift pins have the same circle in plan view. The substrate support portion has a plurality of contact portions made of an elastic body that protrudes upward and contacts the back surface of the substrate. The pitch circles of the plurality of lift pins generate a force acting in a direction inclined with respect to the horizontal to the plurality of contact portions when the back surface of the inclined substrate contacts the plurality of contact portions. The diameter is set.

  The substrate delivery method according to claim 7 is the substrate delivery method according to claim 6, wherein the substrate is made of a disk-shaped member having a diameter of 450 mm, and the pitch circle diameter of the plurality of lift pins is 180 mm or less. And

  The substrate delivery method according to an eighth aspect is the substrate delivery method according to the seventh aspect, wherein a pitch circle diameter of the plurality of lift pins is 120 mm or less.

  According to the present invention, when the substrate is lifted upward by the plurality of lift pins and transferred to the substrate support portion provided on the transfer arm, the substrate is positively deformed upward and the back surface of the substrate is horizontally leveled. When the back surface of the inclined substrate comes into contact with a plurality of contact portions of the substrate support portion provided on the transfer arm, it acts on the plurality of contact portions in a direction inclined with respect to the horizontal. When the substrate is lifted by another lift pin in order to transfer the substrate supported by the substrate support unit to another lift pin, the reaction force of the force acting in the inclined direction causes the holding force in the vertical direction of the substrate to be generated. It acts as a reducing force and assists the separation of the substrate from the plurality of contact portions. Accordingly, the substrate is easily separated from the plurality of contact portions, and the substrate lifted by the other lift pins does not greatly warp. As a result, the substrate does not jump due to the spring force due to warpage, and the substrate can be prevented from being displaced during delivery.

It is a top view which shows roughly the structure of the substrate processing system provided with the substrate conveyance apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the structure of the board | substrate delivery mechanism which concerns on this Embodiment, FIG. 2 (A) is a top view, FIG.2 (B) is a side view. It is process drawing which shows the conventional board | substrate delivery method. It is process drawing which shows the board | substrate delivery method concerning this Embodiment. It is process drawing of the substrate conveying method performed in the substrate processing system of FIG. It is a graph which shows the relationship between PCD of each lift pin and the amount of bending of a wafer. It is a graph which shows the relationship between PCD of each lift pin and the maximum deflection amount of a wafer. FIGS. 8A and 8B are graphs showing wafer displacement when the substrate transfer method of FIG. 5 is executed a plurality of times, FIG. 8A shows a case where the PCD of each lift pin is set to 120 mm, and FIG. This shows a case where the PCD is set to 220 mm. FIGS. 9A and 9B are diagrams schematically illustrating a configuration of a transfer arm in the transfer module, FIG. 9A is a perspective view of the transfer arm, FIG. 9B is a plan view of a fork of the transfer arm, and FIG. C) is a side view of the fork of the transfer arm.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view schematically showing a configuration of a substrate processing system including a substrate transfer apparatus according to the present embodiment. The substrate processing system of FIG. 1 is configured to perform plasma processing on a wafer in a single wafer. In FIG. 1, for the sake of explanation, the substrate processing system is drawn so that the inside of the substrate processing system can be seen through.

  In FIG. 1, a substrate processing system 10 includes a transfer module 11 (substrate transfer chamber) having a substantially pentagonal shape in plan view, and six process modules 12 arranged radially around the transfer module 11 and connected to the transfer module 11. (Substrate processing chamber), a loader module 13 disposed to face the transfer module 11, and two load lock modules 14 (atmospheric vacuum switching chamber) interposed between the transfer module 11 and the loader module 13.

  Each process module 12 is composed of a vacuum chamber and has a stage 15 as a columnar mounting table arranged inside. After the wafer W is placed on the stage 15, the inside of the process module 12 is decompressed to introduce a processing gas. Further, high frequency power is applied inside to generate plasma, and the wafer W is subjected to plasma processing by the plasma. Each process module 12 and the transfer module 11 are partitioned by a gate valve 16 that can be freely opened and closed.

  In addition, the stage 15 of each process module 12 has a plurality of thin rod-like three lift pins 15a that can protrude from the upper surface. Each lift pin 15a is arranged on the same circumference in plan view, and supports and lifts the wafer W placed on the stage 15 by protruding from the upper surface of the stage 15 and supports it by retreating into the stage 15. Wafer W is placed on stage 15.

  The transfer module 11 includes a vacuum chamber, and includes a transfer mechanism 17 including two SCARA arm type transfer arms 17a arranged inside and guide rails (not shown) arranged inside. The transfer mechanism 17 moves along the guide rail and transfers the wafer W between the process modules 12 and the load lock module 14. Each transfer arm 17a is configured to be pivotable and extendable, and a fork 17b (substrate support portion) that supports the wafer W is disposed at the tip of each transfer arm 17a.

  Each load lock module 14 includes an internal pressure variable chamber that can be switched between a vacuum and an atmospheric pressure, and has a columnar stage 18 disposed therein. When the load lock module 14 carries the wafer W from the loader module 13 to the transfer module 11, the load lock module 14 first receives the wafer W from the loader module 13 while maintaining the inside at atmospheric pressure, and then reduces the inside to a vacuum to transfer the wafer W. 11 carries the wafer W. When the wafer W is unloaded from the transfer module 11 to the loader module 13, first, the interior is maintained in a vacuum and the wafer W is received from the transfer module 11, and then the interior is pressurized to atmospheric pressure and the wafer W is transferred to the loader module 13. Carry in.

  The stage 18 of each load lock module 14 has a plurality of thin rod-like three lift pins 18a that can protrude from the upper surface. Each lift pin 18 a is arranged on the same circumference in plan view, and supports and lifts the wafer W by protruding from the upper surface of the stage 18.

  The loader module 13 is composed of a rectangular parallelepiped atmospheric transfer chamber. Each load lock module 14 is connected to one side surface in the longitudinal direction, and three hoop mounting tables 19 are provided on the other side surface in the longitudinal direction.

  A transport mechanism 20 is disposed in the loader module 13. The transport mechanism 20 includes a guide rail (not shown) and a SCARA arm type transport arm 20a, and the transport arm 20a moves along the guide rail. The fork 20b that supports the wafer W is disposed at the tip of the transfer arm 20a. In the loader module 13, the transfer mechanism 20 transfers the wafers W between FOUPs (not shown) as containers for storing a plurality of wafers W mounted on the FOUP mounting tables 19 and the load lock modules 14.

  The substrate processing system 10 includes a control device 21 including, for example, a computer, and the operation of each component (for example, the transfer module 11 and the process module 12) of the substrate processing system 10 is controlled by the control device 21.

  In the substrate processing system 10, each transfer arm 17 a of the transfer mechanism 17 in the transfer module 11 and each lift pin 18 a of the stage 18 in the load lock module 14 constitute a substrate transfer apparatus.

  Note that a substrate transfer method from each load lock module 14 to each process module 12 by each transfer arm 17a, each lift pin 18a and each lift pin 15a will be described in detail later (FIG. 5).

  2A and 2B are diagrams for explaining the configuration of the substrate delivery mechanism according to the present embodiment. FIG. 2A is a plan view and FIG. 2B is a side view. In FIG. 2A, the fork 17b is drawn for the sake of illustration, and the wafer W is indicated by a broken line.

  2A and 2B, the fork 17b of each transfer arm 17a of the transfer mechanism 17 and each lift pin 18a of the stage 18 constitute a substrate delivery mechanism.

  The fork 17b is composed of a bifurcated flat plate member, and has three pads 17c (contact portions) arranged on the same circumference on the upper surface. Each pad 17c is made of an elastic body, for example, heat-resistant rubber, and is a protrusion having at least an upper end having a hemispherical shape.

  In the stage 18, each lift pin 18a is bifurcated when the fork 17b enters the load lock module 14 and the center of the pitch circle of each pad 17c coincides with the center of the pitch circle of each lift pin 18a in plan view. It arrange | positions so that it may be located inside a part. Thereby, each lift pin 18a can protrude upward without interfering with the fork 17b. When the upper end of each lift pin 18a is located above the upper end of each pad 17c of the fork 17b, each lift pin 18a is formed on the wafer W. The wafer W is lifted in contact with the back surface.

  Further, when the upper end of each lift pin 18a is positioned below the upper end of each pad 17c, each pad 17c contacts the back surface of the wafer W to support the wafer W. That is, in the substrate delivery mechanism according to the present embodiment, each lift pin 18a moves up and down in the vertical direction in FIG. 2B, and the wafer W is delivered by changing the relative position with respect to the fork 17b.

  By the way, with respect to the location of each lift pin in plan view, conventionally, when the lift pins are set as large as possible and the wafer is lifted by each lift pin, the outside of the wafer is supported by each lift pin as much as possible to suppress the deflection of the wafer as much as possible. As a result, each pad of the fork 17 is brought into contact with the back surface of the wafer in as large an area as possible. For example, when the diameter of the wafer W is 450 mm, the PCD of each lift pin is set to 220 mm.

  FIG. 3 is a process diagram illustrating a conventional substrate delivery method. FIGS. 3A, 3B, and 3D are cross-sectional views of a fork, a lift pin, and a wafer. ) Is shown as an enlarged cross-sectional view around the pad.

  First, when each lift pin 95 protrudes above the fork 93 to lift the wafer W, the PCD of each lift pin 95 is set as large as possible, so that the deflection of the wafer W is suppressed (FIG. 3A).

  Next, when each lift pin 95 is moved downward, the back surface of the wafer W comes into contact with each pad 94 and is supported by each pad 94 (FIG. 3B), but the deflection of the wafer W is suppressed. Since the inclination of the back surface of the wafer W is small, each pad 94 comes into contact with the back surface of the wafer W with a large area, and the upper end of each pad 94 mainly comes into contact with the back surface of the wafer W. Therefore, almost no force, for example, shearing force, acts in a downwardly inclined direction (hereinafter simply referred to as “inclined direction”) (FIG. 3C).

  Next, when each lift pin 95 moves downward from the fork 93, each pad 94 of the fork 93 comes into contact with the back surface of the wafer W to support the wafer W (FIG. 3D).

  However, as described above, when each pad 94 comes into contact with the back surface of the wafer W in a large area, the wafer W is fixed to each pad 94 to hold the wafer W in the vertical direction (hereinafter referred to as “wafer W”). When the fork 93 supporting the wafer W enters the process module and transfers the wafer W to the lift pins of the stage, the wafer W is lightly moved by the lift pins. The wafer W may not be separated from the fork 93 simply by lifting.

  In the present embodiment, the PCD of each lift pin 18a is correspondingly smaller than the PCD (eg, 220 mm) of each conventional lift pin 18a. Specifically, when the diameter of the wafer W is 450 mm, for example, Set to 120 mm.

  FIG. 4 is a process diagram showing a substrate delivery method according to the present embodiment, and FIGS. 4A, 4B, and 4D are shown as cross-sectional views of a fork, a lift pin, and a wafer. FIG. 4C is an enlarged cross-sectional view around the pad.

  First, when each lift pin 18a protrudes upward from the fork 17b to lift the wafer W, the PCD of each lift pin 18a is set as small as possible. Therefore, the wafer W is greatly bent and positively deformed upward (see FIG. FIG. 4 (A)) (substrate raising step).

  Next, when the lift pins 18a are moved downward to lower the wafer W, the back surface of the wafer W comes into contact with the pads 17c and the wafer W is supported by the pads 17c (FIG. 4B). Since W is positively deformed upward and the back surface of the wafer W is inclined with respect to the horizontal, each pad 17c abuts the back surface of the wafer W with a small area, and mainly the inclination of each pad 17c. The surface comes into contact with the back surface of the wafer W, and the upper end of each pad 17c is deformed in the tilt direction, and a force acting in the tilt direction on each pad 17c, for example, a shearing force 22 is generated (FIG. 4C). Further, wrinkles are generated on the surface of each pad 17c due to the deformation of the upper end in the inclined direction, and the contact area with the wafer W is further reduced.

  Next, when each lift pin 18a moves below the fork 17b, each pad 17c of the fork 17b contacts the back surface of the wafer W to support the wafer W, but each pad 17c is pressed by the wafer W. The deformation of the upper end of 17c in the tilt direction is maintained, and a reaction force 23 along the direction opposite to the tilt direction (the direction tilted upward with respect to the horizontal) acts on the wafer W as a reaction of the shearing force 22 (FIG. 4 (C), FIG. 4 (D)). The component force upward of the reaction force 23 acts as a force to reduce the vertical holding force of the wafer W, and the wafer W is lifted by the lift pins 15a of the stage 15 in the process module 12 in the substrate transfer method (FIG. 5) described later. When being performed, the separation of the wafer W from each pad 17c is assisted.

  FIG. 5 is a process diagram of a substrate transfer method executed in the substrate processing system of FIG. In this substrate transfer method, the wafer W is transferred from the load lock module 14 to the process module 12, and the substrate delivery method of FIG. 4 is executed in the middle of the substrate transfer method. In each figure, the load lock module 14 and the process module 12 are omitted.

  First, the fork 20b of the transfer arm 20a that lifts the wafer W enters the load lock module 14 and opposes the wafer W to the stage 18 (FIG. 5A).

  Next, each lift pin 18a protrudes upward to lift the wafer W and separate it from the fork 20b. However, since the PCD of each lift pin 18a is set as small as possible, it is positively deformed upward (FIG. 5B). )).

  Next, after the fork 20b is withdrawn from the load lock module 14 and the inside of the load lock module 14 is depressurized to a vacuum, the fork 17b of the transfer arm 17a enters the load lock module 14. At this time, the center of the PCD of each pad 17c of the fork 17b coincides with the center of the PCD of each lift pin 18a (FIG. 5C).

  Next, each lift pin 18a moves downward to lower the wafer W, and the wafer W is supported by each pad 17c. As described above, since the back surface of the wafer W is inclined with respect to the horizontal, the wafer W When the back surface of the substrate abuts against each pad 17c, a shearing force 22 along the inclination direction is generated at each pad 17c, and a reaction force 23 along the direction opposite to the inclination direction acts on the wafer W as a reaction of the shearing force 22. (FIGS. 5D and 4C).

  Next, the fork 17 b that supports the wafer W exits from the load lock module 14, enters the process module 12 through the transfer module 11, and makes the wafer W face the stage 15. At this time, the center of the PCD of each pad 17c of the fork 17b coincides with the center of the PCD of each lift pin 15a (FIG. 5E).

  Next, each lift pin 15a protrudes upward to lift the wafer W and separate it from the fork 17b. At this time, the component force toward the upper side of the reaction force 23 acts as a force for reducing the vertical holding force of the wafer W. Is pushed upward to assist the separation of the wafer W from each pad 17c (FIG. 5F).

  Next, after the fork 17b is withdrawn from the process module 12, each lift pin 15a moves downward to lower the wafer W and place the wafer W on the stage 15 (FIG. 5G). finish.

  According to the substrate delivery method of FIG. 4 and the substrate transfer method of FIG. 5, when the wafer W is lifted upward by the lift pins 18a and transferred to the forks 17b provided on the transfer arm 17a, the wafer W is positively received. When the rear surface of the wafer W is in contact with the pad 17c of the fork 17b, the shearing force 22 along the tilt direction is applied to the pad 17c. Therefore, when the wafer W is lifted by the lift pins 15a in order to transfer the wafer W supported by the fork 17b to the lift pins 15a, the reaction force 23 as a reaction of the shearing force 22 separates the wafer W from the pad 17c. Assist. Further, wrinkles are generated on the surface of each pad 17c due to the deformation of the upper end in the inclined direction, and the contact area with the wafer W is further reduced, so that the wafer W is hardly fixed to each pad 17c. Thereby, the wafer W is easily separated from each pad 17c, and the wafer W lifted by each lift pin 15a does not greatly warp. As a result, the wafer W does not jump due to the spring force caused by the warp, and the wafer W can be prevented from shifting.

  Further, in the substrate processing system 10 described above, at least the upper end of the pad 17c has a hemispherical shape, so that the contact between the inclined back surface of the wafer W and the pad 17c is easy and the contact area between the back surface of the wafer W Therefore, it is possible to reliably prevent the wafer W from sticking to each pad 17c.

  Although the present invention has been described using the above embodiment, the present invention is not limited to the above embodiment.

  For example, the stage 18 has three lift pins 18a, but the number of lift pins 18a is not limited to three, and may be four or more as long as the wafer W can be stably supported.

  In addition, since it is necessary to place the wafer W at a predetermined position (processing position) on the stage 15 in the process module 12, the present invention is applied to transfer of the wafer W from the load lock module 14 to the process module 12. However, the present invention may be applied to transfer of the wafer W after the wafer W is subjected to plasma processing in the process module 12, for example, transfer from the process module 12 to the load lock module 14.

  Furthermore, in the above-described embodiment, the shearing force 22 is taken as an example of the force acting in the inclination direction generated in each pad 17c when the back surface of the wafer W is inclined with respect to the horizontal and comes into contact with each pad 17c. The force acting in the tilt direction is not limited to the shearing force 22.

  Next, examples of the present invention will be specifically described.

  First, using a wafer W having a diameter of 450 mm, the deflection amount of the wafer W was measured when the PCD of each lift pin 18a was set to 120 mm as Example 1, and the PCD of each lift pin 18a was set to 180 mm as Example 2. 6 is measured, and as Comparative Example 1, the deflection amount of the wafer W when the PCD of each lift pin 18a is set to 220 mm is measured, and each measured deflection amount is shown in the graph of FIG. . In the graph of FIG. 6, the horizontal axis represents the distance from the center of the wafer, and the vertical axis represents the amount of deflection of the wafer.

  Further, as a third to seventh embodiments, a wafer W having a diameter of 450 mm is used, and the deflection amount of the wafer W is simulated when the PCD of each lift pin 18a is set to 112 mm, 132 mm, 152 mm, 172 mm, and 192 mm, respectively. 7 to 4, the bending amount of the wafer W was simulated when the PCD of each lift pin 18 a was set to 212 mm, 232 mm, and 252 mm, respectively. The simulated maximum bending amount is shown in the graph of FIG. 7. In the graph of FIG. 7, the horizontal axis indicates the PCD of the lift pin, and the vertical axis indicates the maximum deflection amount.

  From the graphs of FIG. 6 and FIG. 7, the smaller the PCD of each lift pin 18a, the more the wafer W is deformed upward and bent, and the back surface of the wafer W can be greatly inclined with respect to the horizontal. I understood. Therefore, from the viewpoint of preventing the wafer W from shifting when the wafer W is separated from the transfer arm 17a, it is preferable to reduce the PCD of each lift pin 18a, and at least the PCD of each lift pin 18a in the conventional substrate delivery method. It turned out that it is preferable to set it to smaller than 220 mm, for example, 180 mm or less.

  5 is executed a plurality of times using a wafer W having a diameter of 450 mm, the wafer W is positioned relative to the processing position on the stage 15 of the process module 12 when the PCD of each lift pin 18a is set to 120 mm. The deviation was measured as Example 8, and the deviation of the wafer W relative to the processing position on the stage 15 when the PCD of each lift pin 18a was set to 220 mm was measured as Comparative Example 5, and the wafer measured in Example 8 was measured. The deviation of W is shown in the graph of FIG. 8A, and the deviation of the wafer W measured in Comparative Example 5 is shown in the graph of FIG. 8B.

  In Example 8, the deviation of the wafer W was within the range of 0.2 mm in diameter (indicated by a circle in the figure), whereas in Comparative Example 5, the deviation of the wafer W was not within the range of 0.2 mm in diameter. It was found that it was barely within the range of 0.5 mm in diameter (indicated by a circle in the figure), and the deviation was unevenly distributed. Further, when Example 8 and Comparative Example 5 were compared, it was found that the shift of the wafer W became smaller as the PCD of each lift pin 18a was made smaller. Therefore, it was found that the PCD of each lift pin 18a is preferably set to 120 mm or less in order to keep the deviation of the wafer W within the range of 0.2 mm in diameter.

W Wafer 10 Substrate processing system 11 Transfer module 12 Process module 14 Load lock module 17a Transfer arm 17b Fork 17c Pad 18 Stage 18a Lift pin

Claims (8)

A substrate delivery mechanism comprising a plurality of lift pins for lifting the substrate upward to deliver the substrate to a substrate support provided on a transfer arm;
The plurality of lift pins are arranged on the same circumference in plan view,
The substrate support portion has a plurality of contact portions made of an elastic body that protrudes upward and contacts the back surface of the substrate.
The pitch circle diameter of the plurality of lift pins is such that when the plurality of lift pins lifts the substrate upward, the substrate positively deforms upward and the back surface of the substrate is inclined with respect to the horizontal, The substrate is set so as to generate a force acting on the plurality of contact portions in a direction inclined with respect to the horizontal when the back surface of the inclined substrate contacts the plurality of contact portions. Delivery mechanism. The substrate delivery mechanism according to claim 1, wherein at least an upper end of the contact portion has a hemispherical shape. The substrate delivery mechanism according to claim 1 or 2, wherein the substrate is made of a disk-like member having a diameter of 450 mm, and the pitch circle diameter of the plurality of lift pins is 180 mm or less. 4. The substrate delivery mechanism according to claim 3, wherein a pitch circle diameter of the plurality of lift pins is 120 mm or less. In a substrate processing system comprising an atmospheric vacuum switching chamber, a substrate processing chamber, and a substrate transfer chamber interposed between the atmospheric vacuum switching chamber and the substrate processing chamber, a substrate between the substrate processing chamber and the atmospheric vacuum switching chamber A substrate transfer device for transferring
A transfer arm that is disposed in the substrate transfer chamber and has a substrate support portion that is movable back and forth to the atmospheric vacuum switching chamber and the substrate processing chamber;
A plurality of lift pins disposed in the atmospheric vacuum switching chamber and lifting the substrate upward to deliver the substrate to the substrate support;
The plurality of lift pins are arranged on the same circumference in plan view,
The substrate support portion has a plurality of contact portions made of an elastic body that protrudes upward and contacts the back surface of the substrate.
The pitch circle diameter of the plurality of lift pins is such that when the plurality of lift pins lifts the substrate upward, the substrate positively deforms upward and the back surface of the substrate is inclined with respect to the horizontal, The substrate is set so as to generate a force acting on the plurality of contact portions in a direction inclined with respect to the horizontal when the back surface of the inclined substrate contacts the plurality of contact portions. Conveying device. A substrate delivery method for delivering a substrate with a plurality of lift pins to a substrate support provided on a transfer arm,
When the substrate is lifted upward by the plurality of lift pins, the vicinity of the center of the substrate is supported by the plurality of lift pins, and the substrate is positively deformed upward and the back surface of the substrate is inclined with respect to the horizontal. A substrate raising step,
A substrate lowering step of lowering the substrate with the plurality of lift pins and supporting the substrate on the substrate support portion while supporting the substrate with the plurality of lift pins;
The plurality of lift pins are arranged on the same circumference in plan view,
The substrate support portion has a plurality of contact portions made of an elastic body that protrudes upward and contacts the back surface of the substrate.
When the back surface of the inclined substrate is in contact with the plurality of contact portions in the multiple substrate lowering step, the force is applied to the plurality of contact portions in a direction inclined with respect to the horizontal. A substrate delivery method, wherein pitch circle diameters of a plurality of lift pins are set. The substrate delivery method according to claim 6, wherein the substrate is made of a disk-like member having a diameter of 450 mm, and a pitch circle diameter of the plurality of lift pins is 180 mm or less. The substrate delivery method according to claim 7, wherein a pitch circle diameter of the plurality of lift pins is 120 mm or less.

Images